Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

v?Log2

Computes the base 2 logarithm of vector elements.

Syntax

call vslog2
(
n
,
a
,
y
)
call vslog2i(n, a, inca, y, incy)
call vmslog2
(
n
,
a
,
y
,
mode
)
call vmslog2i(n, a, inca, y, incy, mode)
call vdlog2
(
n
,
a
,
y
)
call vdlog2i(n, a, inca, y, incy)
call vmdlog2
(
n
,
a
,
y
,
mode
)
call vmdlog2i(n, a, inca, y, incy, mode)
Include Files
  • mkl_vml.f90
Input Parameters
Name
Type
Description
n
INTEGER
Specifies the number of elements to be calculated.
a
REAL
for
vslog2
REAL
for
vmslog2
DOUBLE PRECISION
for
vdlog2
DOUBLE PRECISION
for
vmdlog2
Pointer to the array containing the input vector
a
.
inca
,
incy
INTEGER, INTENT(IN)
Specifies increments for the elements of
a
and
y
.
mode
INTEGER (KIND=8)
Overrides the global VM
mode
setting for this function call. See
vmlSetMode
for possible values and their description.
Output Parameters
Name
Type
Description
y
REAL
for
vslog2
REAL
for
vmslog2
DOUBLE PRECISION
for
vdlog2
DOUBLE PRECISION
for
vmdlog2
Pointer to an array containing the output vector
y
.
Description
The
v?Log2
function computes the base 2 logarithm of vector elements.
See Special Value Notations for the conventions used in this table:
Special values for Real Function
v?Log2(x)
Argument
Result
VM Error Status
Exception
+1
+0
x
< +0
QNAN
VML_STATUS_ERRDOM
INVALID
+0
-
VML_STATUS_SING
ZERODIVIDE
-0
-
VML_STATUS_SING
ZERODIVIDE
-
QNAN
VML_STATUS_ERRDOM
INVALID
+
+
QNAN
QNAN
SNAN
QNAN
INVALID